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Nanoporous gold as obtained by corrosion of alloys of gold and a less noble metal is a system with manifold applications. The process of dealloying, however, can result in partially porous samples, when dealloying conditions are not optimized with respect to composition and pre-treatment of the master alloy. In the present work, we investigate the dealloying interface between porous material and non-porous alloy in two samples, in which dealloying either stopped automatically or was interrupted manually. Reasons for unintended termination of dealloying in the former case are suggested.

Reversible macroscopic length changes in nanoporous structures can be achieved by applying electric potentials or by exposing them to different gases or liquids. Thus, these materials are interesting candidates for applications as sensors or actuators. Macroscopic length changes originate from microscopic changes of crystal lattice parameters. In this report, we show spatially resolved measurements of crystal lattice strain in dealloyed nanoporous gold. The results confirm theory by indicating a compression of the lattice along the axis of cylindrically shaped ligaments and an expansion in radial direction. Furthermore, we show that curved npAu surfaces show inward relaxation of the surface layer.